[web] Add startup metrics (#25277)

* [web] refactor startup sequence

The primary objective here is to call loadGlobalBlobs() only once.
But to get there, we need to reorder things and add extra try/catch
sections to ensure we are not letting the global uncaughtException
handler catch startup errors.

Co-authored-by: Antoine Clausse <antoine.clausse@overleaf.com>

* [web] add metrics for startup steps

Co-authored-by: Antoine Clausse <antoine.clausse@overleaf.com>

---------

Co-authored-by: Jakob Ackermann <jakob.ackermann@overleaf.com>
GitOrigin-RevId: c73edea02516e919d55b896588dcd1862835fedf

services/web/app/src/infrastructure/Modules.js

@@ -4,6 +4,7 @@ const { promisify, callbackify } = require('util')
 const Settings = require('@overleaf/settings')
 const Views = require('./Views')
 const _ = require('lodash')
+const Metrics = require('@overleaf/metrics')
 
 const MODULE_BASE_PATH = Path.join(__dirname, '/../../../modules')
 
@@ -15,7 +16,11 @@ let _viewIncludes = {}
 
 async function modules() {
   if (!_modulesLoaded) {
+    const beforeLoadModules = performance.now()
     await loadModules()
+    Metrics.gauge('web_startup', performance.now() - beforeLoadModules, 1, {
+      path: 'loadModules',
+    })
   }
   return _modules
 }

services/web/app/src/infrastructure/Server.mjs

@@ -372,6 +372,10 @@ if (Settings.enabledServices.includes('web')) {
 metrics.injectMetricsRoute(webRouter)
 metrics.injectMetricsRoute(privateApiRouter)
 
+const beforeRouterInitialize = performance.now()
 await Router.initialize(webRouter, privateApiRouter, publicApiRouter)
+metrics.gauge('web_startup', performance.now() - beforeRouterInitialize, 1, {
+  path: 'Router.initialize',
+})
 
 export default { app, server }